The invention relates to a device for heating the recording fluid in a recording head, of an ink mosaic recorder, which head contains a plurality of ink discharge orifices.
In ink mosaic recorders the recording fluid is fed from a reservoir through a delivery duct to a recording head, with the latter, in dependence upon the mosaic screen employed, containing a plurality of individual ink ducts which are individually surrounded by respective piezoelectric control elements. In the recording operation such piezoelectric control elements contract in synchronism with an image generator, to thereby discharge, out of the individual ink ducts, individual droplets of ink which are deposited on the recording medium or carrier.
The quality of reproduction obtainable from such an ink mosaic recorder is materially dependent, among other things, upon the viscosity of the recording fluid. If the latter is of low viscosity, the formation of droplets is made more difficult and it is possible for double droplets to be forced out of the orifices of the ink ducts, considerably impairing the recorded image. If the viscosity of the recording fluid is increased, the droplet formation is improved with a corresponding improvement in the recorded image. On the other hand, such an increase in viscosity has the disadvantage that variations in temperature, particularly within the range of normal room temperature, have themselves a very marked effect upon the viscosity. Consequently, in order to obtain a uniform image reproduction, which is independent of temperature, it is necessary to maintain the viscosity, as far as possible, uniform over a wide temperature range.
An arrangement is known, from German Inspection Specification No. 2,433,510 in which an intermediate chamber between the ink outlet and the ink reservoir has incorporated therewith a heating arrangement for warming the ink up to a temperature above the ambient temperature. in this disclosure, the heating arrangement is utilized primarily for the removal of gas from the recording fluid and to ensure that the recording ink, as a result of the increased temperature thereof, will rapidly become wipe or smear resistant on the recording medium or carrier.